Physical Sciences and Mathematics Commons^™

Fabricating Nanophotonic Devices Using Nanofabrication Techniques, Scott Cummings

Student Scholar Symposium Abstracts and Posters

Nanofabrication processes are widely used to make the integrated circuits and computer chips that are ubiquitous in today’s technology. These fabrication processes can also be applied to the creation of nanophotonic devices. The ways in which we apply these fabrication techniques in the field of photonics is often constrained by the technologies used for electronics manufacturing which presents an interesting engineering challenge. These limitations include availability and cost of certain fabrication equipment and techniques required to create state-of-the-art nanophotonic devices. Through work with the University of California Irvine nano-fabrication cleanroom, we designed and fabricated various integrated photonic components including grating …

Improving The Success Of Non-Traditional Students In An Introductory Computing Course, Christine F. Reilly, Laura M. Grabowski, Gustavo Dietrich

Computer Science Faculty Publications

This Work in Progress Research to Practice paper presents a redesign of an introduction to computing course at a public, minority serving institution in the United States with a majority of non-traditional students. The course redesign was motivated by the desire to improve the success of the students in this course and in the major. Active learning during class and required attendance were the major components of the course redesign. The course policies included flexibility for the occasional absences that are expected with non-traditional students. A comparison of student performance in the experimental and control sections indicated that the requirement …

Absolute Neutral Densities And Temperatures And Their Climatologies In The Middle Atmosphere Using An Optimal Estimation Method With Rayleigh-Scatter Lidar Observations Obtained At Utah State University, Jonathan L. Price

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Earth’s atmosphere is comprised of layers which can be defined by their temperature characteristics. These layers are the troposphere, stratosphere, mesosphere and thermosphere. The region where life exists is in the troposphere, however the study of the layers above is important as changes in these regions can directly impact, or indicate significant changes in, weather in the troposphere. The mesosphere is the least well-known region because it is the most difficult to observe. One of the best tools for observing this region is the Rayleigh-scatter lidar. It is capable of remotely observing the entirety of the mesosphere with good …

Valley Bottom Inundation Patterns In Beaver-Modified Streams: A Potential Proxy For Hydrologic Inefficiency, Karen Bartelt

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

For centuries river management and land use actions in North America have caused widespread stream degradation where water now flows downstream with artificially high efficiency. When present, beaver dams slow the flow of water and decrease the efficiency of water conveyance through the landscape. These effects are often to the benefit of the function of natural physical processes and ecology of the stream. The benefits provided by beaver dams have been well studied at small scales, but the methods that these studies rely on are often expensive and time consuming and consequently not feasible to deploy at larger spatial scales …

Achieving A Sequenced, Relational Query Language With Log-Segmented Timestamps, M. A. Manazir Ahsan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In a relational temporal database, typically each row of each table has a period timestamp to indicate the lifetime of that row. In order to evaluate a query in a temporal database, sequenced semantics comes into play. The semantics stipulates that the query must be evaluated simultaneously in each time instant using the data rows available at that point of time. Existing researches have proposed changes in the query evaluation engine to achieve sequenced semantics. In this paper we show a way to support sequenced semantics without modifying the query engine. We propose a noble construction log-segmented label to represent …

Gps-Denied Navigation Using Synthetic Aperture Radar Images And Neural Networks, Teresa White

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Unmanned aerial vehicles (UAV) often rely on GPS for navigation. GPS signals, however, are very low in power and easily jammed or otherwise disrupted. This paper presents a method for determining the navigation errors present at the beginning of a GPS-denied period utilizing data from a synthetic aperture radar (SAR) system. This is accomplished by comparing an online-generated SAR image with a reference image obtained a priori. The distortions relative to the reference image are learned and exploited with a convolutional neural network to recover the initial navigational errors, which can be used to recover the true flight trajectory throughout …

The Internal Charge Evolution Of Multilayered Materials Undergoing Mono-Energetic Electron Bombardment, Gregory Wilson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The charging of multilayer materials as related to the charging of spacecraft is one of the primary concerns related to activities in the space environment. To understand how multilayer materials undergoing electron bombardment charge, an in-depth study of energy-dependent material properties must be undertaken. These properties include the electron penetration depth, secondary electron emission, charge transport and electrostatic discharge. By using energy dependent models of these properties, along with the geometry of the system, multilayer models can be developed to predict the time evolution of the internal charge distribution. Using these models, the net surface potential and the measurement of …

Characterizing Relational Values To Inform Message-Framing At The Boa Ogoi Historical Site, Cole G. Stocker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In an increasingly polarized political climate–particularly in the U.S.– environmental issues such as climate change and its effects on the environment have become hot-button partisan talking points resulting in further division. This has led to research on ways to communicate science which does not further inflame political tensions, but rather reinforces and validates the audience’s values. Science communication research provides the foundation for my case study, which focuses on characterizing the environmental values and worldviews of land managers residing and working near the Boa Ogoi Historical Site in southern Idaho. The Northwest Band of Shoshone Nation (NWBSN) is in the …

Tractor Connections For Killing Tensors And Their Generalizations, Benjamin D. Shaw

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

We create new symbolic software tools for the analysis of Killing tensors. Central to our work is the construction of the tractor connection defined on the tractor bundle, which allows one to obtain information about the space of Killing tensors without solving the Killing equations–an approach termed the tractor approach. We give a new application of the tractor approach which allows one to more easily check explicitly for linear independence of a given set of Killing tensors. We develop software to implement such methods in the case of rank 2 Killing tensors; similarly, we develop software to implement analogous methods …

Intelligent Traffic Management: From Practical Stochastic Path Planning To Reinforcement Learning Based City-Wide Traffic Optimization, Kamilia Ahmadi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This research focuses on intelligent traffic management including stochastic path planning and city scale traffic optimization. Stochastic path planning focuses on finding paths when edge weights are not fixed and change depending on the time of day/week. Then we focus on minimizing the running time of the overall procedure at query time utilizing precomputation and approximation. The city graph is partitioned into smaller groups of nodes and represented by its exemplar. In query time, source and destination pairs are connected to their respective exemplars and the path between those exemplars is found. After this, we move toward minimizing the city …

On Predicting Omnidirectional Honey Bee Traffic Using Weather And Electromagnetic Radiation, Daniel G. Hornberger

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Honey bees are responsible for pollinating many important crops in the United States. However, honey bee populations have declined significantly since 1961. While some causes of this decline are known, others are not. By utilizing electronic bee hive monitoring (EBM) systems, bee keepers and researchers have an added resource in determining the causes of these declines so that the issues can be remedied. For nearly five months (May through October) during the 2020 honey bee foraging season in Logan, Utah, USA, we collected on-site weather and electromagnetic radiation (EMR) readings and videos of the hive entrances of six bee hives …

Predictive Models Of Post-Wildfire Debris Flow Volume And Grain Size Distribution In The Intermountain West, Sara Wall

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Post-fire debris flows represent the most erosive and potentially hazardous consequence associated with increasing wildfire severity. While an abundance of research has explored where they are likely to occur and their potential magnitude, investigations into understanding how they impact downstream resources are limited. Recent advancements are seeking to link predictive models together to be able to predict how erosion after wildfire may impact reservoirs and aquatic habitat downstream. However, there are two key missing pieces into our ability to examine watershed-scale impacts of post-fire erosion. These include having accurate predictions of how much sediment is likely to be deposited by …

On The Geometry Of The Moduli Space Of Certain Lattice Polarized K3 Surfaces And Their Picard-Fuchs Operators, Michael T. Schultz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

K3 surfaces have a long and rich study in mathematics, and more recently in physics via string theory. Often, K3 surfaces come in multiparameter families - the parameters describing these surfaces fit together to form their own geometric space, a so-called moduli space. In particular, the moduli spaces of K3 surfaces equipped with a lattice polarization can sometimes be constructed explicitly, which subsequently reveals important information about the original K3 surface.

In this work, we construct such families explicitly from certain rational elliptic surfaces via the so-called mixed-twist construction of Doran & Malmendier, which in turn produces the moduli …

Graph Learning Assisted Multi-Objective Integer Programming, Yaoxin Wu, Wen Song, Zhiguang Cao, Jie Zhang, Abhishek Gupta, Mingyan Simon Lin

Research Collection School Of Computing and Information Systems

Objective-space decomposition algorithms (ODAs) are widely studied for solvingmulti-objective integer programs. However, they often encounter difficulties inhandling scalarized problems, which could cause infeasibility or repetitive nondominatedpoints and thus induce redundant runtime. To mitigate the issue, we presenta graph neural network (GNN) based method to learn the reduction rule in the ODA.We formulate the algorithmic procedure of generic ODAs as a Markov decisionprocess, and parameterize the policy (reduction rule) with a novel two-stage GNNto fuse information from variables, constraints and especially objectives for betterstate representation. We train our model with imitation learning and deploy it ona state-of-the-art ODA. Results show that …

Statistical Moderation: A Case Study In Grading On A Curve, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

There is a negative perception about “grading on a curve,” because of the feeling that the cohort strength may skew the final grades one way or another. However, given the difficulties in ensuring absolute uniformity in assessment across the years, especially when taught and assessed by different instructors under different settings, grading on a curve may be a necessary evil. Once we accept this type of statistical moderation as the last line of defense in standardizing the final scores so that student cohorts from different terms or sections or schools may be compared, we have to implement it well. In …

Context-Aware Graph Convolutional Network For Dynamic Origin-Destination Prediction, Juan Nathaniel, Baihua Zheng

Research Collection School Of Computing and Information Systems

A robust Origin-Destination (OD) prediction is key to urban mobility. A good forecasting model can reduce operational risks and improve service availability, among many other upsides. Here, we examine the use of Graph Convolutional Net-work (GCN) and its hybrid Markov-Chain (GCN-MC) variant to perform a context-aware OD prediction based on a large-scale public transportation dataset in Singapore. Compared with the baseline Markov-Chain algorithm and GCN, the proposed hybrid GCN-MC model improves the prediction accuracy by 37% and 12% respectively. Lastly, the addition of temporal and historical contextual information further improves the performance of the proposed hybrid model by 4 –12%.

Hrpdf: A Software-Based Heterogeneous Redundant Proactive Defense Framework For Programmable Logic Controller, Ke Liu, Jing-Yi Wang, Qiang Wei, Zhen-Yong Zhang, Jun Sun, Rong-Kuan Ma, Rui-Long Deng

Research Collection School Of Computing and Information Systems

Programmable logic controllers (PLCs) play a critical role in many industrial control systems, yet face increasingly serious cyber threats. In this paper, we propose a novel PLC-compatible software-based defense mechanism, called Heterogeneous Redundant Proactive Defense Framework (HRPDF). We propose a heterogeneous PLC architecture in HRPDF, including multiple heterogeneous, equivalent, and synchronous runtimes, which can thwart multiple types of attacks against PLC without the need of external devices. To ensure the availability of PLC, we also design an inter-process communication algorithm that minimizes the overhead of HRPDF. We implement a prototype system of HRPDF and test it in a real-world PLC …

Linear Algebra For Computer Science, M. Thulasidas

Research Collection School Of Computing and Information Systems

This textbook introduces the essential concepts and practice of Linear Algebra to the undergraduate student of computer science. The focus of this book is on the elegance and beauty of the numerical techniques and algorithms originating from Linear Algebra. As a practical handbook for computer and data scientists, LA4CS restricts itself mostly to real fields and tractable discourses, rather than deep and theoretical mathematics.

Strategic Behavior And Market Inefficiency In Blockchain-Based Auctions, Ping Fan Ke, Jianqing Chen, Zhiling Guo

Research Collection School Of Computing and Information Systems

Blockchain-based auctions play a key role in decentralized finance, such as liquidation of collaterals in crypto-lending. In this research, we show that a Blockchain-based auction is subject to the threat to availability because of the characteristics of the Blockchain platform, which could lead to auction inefficiency or even market failure. Specifically, an adversary could occupy all of the transaction capacity of an auction by sending transactions with sufficiently high transaction fees, and then win the item in an auction with a nearly zero bid price as there are no competitors available. We discuss how to prevent this kind of strategic …

Concise Mercurial Subvector Commitments: Definitions And Constructions, Yannan Li, Willy Susilo, Guomin Yang, Tran Viet Xuan Phuong, Yong Yu, Dongxi Liu

Research Collection School Of Computing and Information Systems

Vector commitment and its variants have attracted a lot of attention recently as they have been exposed to a wide range of applications in blockchain. Two special extensions of vector commitments, namely subvector commitments and mercurial commitments, have been proposed with attractive features that are desirable in many applications. Nevertheless, to the best of our knowledge, a single construction satisfying all those attractive features is still missing. In this work, we analyze those important properties and propose a new primitive called mercurial subvector commitments, which are efficiently updatable, mercurial hiding, position binding, and aggregatable. We formalize the system model and …

Broadcast Authenticated Encryption With Keyword Search, Xueqiao Liu, Kai He, Guomin Yang, Willy Susilo, Joseph Tonien, Qiong Huang

Research Collection School Of Computing and Information Systems

The emergence of public-key encryption with keyword search (PEKS) has provided an elegant approach to enable keyword search over encrypted content. Due to its high computational complexity proportional to the number of intended receivers, the trivial way of deploying PEKS for data sharing with multiple receivers is impractical, which motivates the development of a new PEKS framework for broadcast mode. However, existing works suffer from either the vulnerability to keyword guessing attacks (KGA) or high computation and communication complexity. In this work, a new primitive for keyword search in broadcast mode, named broadcast authenticated encryption with keyword search (BAEKS), is …

Challenges For Estimating The Global Prevalence Of Micronutrient Deficiencies And Related Disease Burden: A Case Study Of The Global Burden Of Disease Study, Sonja Y. Hess, Alexander C. Mclain Ph.D., Edward A. Frongillo Jr. Ph.D., Ashkan Afshin, Nicholas J. Kassebaum, Saskia Jm Osendarp, Reed Atkin, Rahul Rawat, Kenneth H. Brown

Faculty Publications

Information on the prevalence of micronutrient deficiencies is needed to determine related disease burden; underpin evidence-based advocacy; and design, deliver, and monitor safe, effective interventions. Assessing the global prevalence of deficiency requires a valid micronutrient status biomarker with an appropriate cutoff to define deficiency and relevant data from representative surveys across multiple locations and years. The Global Burden of Disease Study includes prevalence estimates for iodine, iron, zinc, and vitamin A deficiencies, for which recommended biomarkers and appropriate deficiency cutoffs exist. Because representative survey data are lacking, only retinol concentration is used to model vitamin A deficiency, and proxy indicators …

Smooth Loops And Loop Bundles, Sergey Grigorian

School of Mathematical & Statistical Sciences Faculty Publications

A loop is a rather general algebraic structure that has an identity element and division, but is not necessarily associative. Smooth loops are a direct generalization of Lie groups. A key example of a non-Lie smooth loop is the loop of unit octonions. In this paper, we study properties of smooth loops and their associated tangent algebras, including a loop analog of the Maurer-Cartan equation. Then, given a manifold, we introduce a loop bundle as an associated bundle to a particular principal bundle. Given a connection on the principal bundle, we define the torsion of a loop bundle structure and …

Hierarchical Control Of Multi-Agent Reinforcement Learning Team In Real-Time Strategy (Rts) Games, Weigui Jair Zhou, Budhitama Subagdja, Ah-Hwee Tan, Darren Wee Sze Ong

Research Collection School Of Computing and Information Systems

Coordinated control of multi-agent teams is an important task in many real-time strategy (RTS) games. In most prior work, micromanagement is the commonly used strategy whereby individual agents operate independently and make their own combat decisions. On the other extreme, some employ a macromanagement strategy whereby all agents are controlled by a single decision model. In this paper, we propose a hierarchical command and control architecture, consisting of a single high-level and multiple low-level reinforcement learning agents operating in a dynamic environment. This hierarchical model enables the low-level unit agents to make individual decisions while taking commands from the high-level …

Automated Doubt Identification From Informal Reflections Through Hybrid Sentic Patterns And Machine Learning Approach, Siaw Ling Lo, Kar Way Tan, Eng Lieh Ouh

Research Collection School Of Computing and Information Systems

Do my students understand? The question that lingers in every instructor’s mind after each lesson. With the focus on learner-centered pedagogy, is it feasible to provide timely and relevant guidance to individual learners according to their levels of understanding? One of the options available is to collect reflections from learners after each lesson to extract relevant feedback so that doubts or questions can be addressed in a timely manner. In this paper, we derived a hybrid approach that leverages a novel Doubt Sentic Pattern Detection (SPD) algorithm and a machine learning model to automate the identification of doubts from students’ …

Data Fusion For Trust Evaluation, Zheng Yan, Qinghua Zheng, Laurence T. Yang, Robert H. Deng

Research Collection School Of Computing and Information Systems

Trust evaluation is a process to quantify trust by analyzing the data related to the factors that affect trust. It has been widely applied in many fields to facilitate decision making, system entity collaboration and security establishment. For example, in social networking, trust evaluation helps users make a social decision, reduce the risk of social interactions, and ensure the quality of a social networking environment. In digital communications, trust evaluation can be applied to detect malicious nodes, filter unwanted traffic and improve communication security. In e-commerce and cloud services, trust evaluation helps users selecting an appropriate product or service from …

Robust Bipoly-Matching For Multi-Granular Entities, Ween Jiann Lee, Maksim Tkachenko, Hady W. Lauw

Research Collection School Of Computing and Information Systems

Entity matching across two data sources is a prevalent need in many domains, including e-commerce. Of interest is the scenario where entities have varying granularity, e.g., a coarse product category may match multiple finer categories. Previous work in one-to-many matching generally presumes the `one' necessarily comes from a designated source and the `many' from the other source. In contrast, we propose a novel formulation that allows concurrent one-to-many bidirectional matching in any direction. Beyond flexibility, we also seek matching that is more robust to noisy similarity values arising from diverse entity descriptions, by introducing receptivity and reclusivity notions. In addition …

On Analysing Student Resilience In Higher Education Programs Using A Data-Driven Approach, Audrey Tedja Widjaja, Ee Peng Lim, Aldy Gunawan

Research Collection School Of Computing and Information Systems

Analysing student resilience is important as research has shown that resilience is related to students’ academic performance and their persistence through academic setbacks. While questionnaires can be conducted to assess student resilience directly, they suffer from human recall errors and deliberate suppression of true responses. In this paper, we propose ACREA, ACademic REsilience Analytics framework which adopts a datadriven approach to analyse student resilient behavior with the use of student-course data. ACREA defines academic setbacks experienced by students and measures how well students overcome such setbacks using a quasi-experimental design. By applying ACREA on a real world student-course dataset, we …

Microservices Orchestration Vs. Choreography: A Decision Framework, Alan @ Ali Madjelisi Megargel, Christopher M. Poskitt, Shankararaman, Venky

Research Collection School Of Computing and Information Systems

Microservices-based applications consist of loosely coupled, independently deployable services that encapsulate units of functionality. To implement larger application processes, these microservices must communicate and collaborate. Typically, this follows one of two patterns: (1) choreography, in which communication is done via asynchronous message-passing; or (2) orchestration, in which a controller is used to synchronously manage the process flow. Choosing the right pattern requires the resolution of some trade-offs concerning coupling, chattiness, visibility, and design. To address this problem, we propose a decision framework for microservices collaboration patterns that helps solution architects to crystallize their goals, compare the key factors, and then …

Vireo @ Trecvid 2021 Ad-Hoc Video Search, Jiaxin Wu, Phuong Anh Nguyen, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

In this paper, we summarize our submitted runs and results for Ad-hoc Video Search (AVS) task at TRECVid 2020